JP5902589B2 - Image processing device - Google Patents

Description

  The present invention relates to image processing, such as shading correction processing and noise suppression processing.

  Digital cameras have been installed in small devices such as mobile phones, and demands for thinning, downsizing, and price reduction are becoming stricter. In order to satisfy these requirements, the performance of the lens is limited, so that various corrections are performed on the image obtained by imaging to improve the image quality.

  For example, “shading” in which the amount of transmitted light decreases as the distance from the center of the lens decreases is a phenomenon that generally occurs, and it is basically essential to perform shading correction on an image obtained by imaging. (Patent Documents 1 and 2).

  Shading correction is generally a process of multiplying an image by a gain that increases from the center of the lens toward the outer periphery in accordance with the image height of the lens. The pixel position in the radial direction centered on the lens center corresponds to the image height of the lens, and unless otherwise specified, “pixel position” refers to the pixel position in the radial direction centered on the image center. means.

  Since the noise increases in the pixels located on the outer periphery by the shading correction, noise suppression processing (NR: Noise Reduction) is performed on the image subjected to the shading correction.

  However, since the NR that suppresses the noise increased by shading correction usually applies the same level of noise suppression to the entire image, the noise distribution over the entire image, such as the image after shading correction, is uniform. In the case of an image that is not, the setting is such that noise is removed in accordance with the average value or maximum value of the noise increased by the correction. As a result, the portion of the center of the image where the gain is hardly applied in the shading correction is blurred due to excessive NR, and image quality deterioration such as detail reduction occurs.

  In some cases, noise suppression processing is performed before shading correction. In this case, if a strong noise suppression process is performed in consideration of shading correction to be performed later, the detail in the center portion of the image is reduced due to excessive NR. On the other hand, if noise suppression processing with weak intensity is performed in order to preserve the details of the central portion of the image, the noise in the outer peripheral portion of the image is amplified by the subsequent shading correction.

  In Patent Document 3, as a technique for solving this problem, a technique for determining whether to perform noise suppression processing depending on whether a shading correction amount (corresponding to a gain) is less than a threshold value or less than a threshold value. Is disclosed. According to this technique, the noise suppression process is performed on the pixels in the portion with the large gain, and the noise suppression processing is not performed on the pixels in the portion with the small gain. The blur in the center can be prevented.

  However, since this technology determines whether or not to perform noise suppression processing according to the shading correction amount, a boundary is formed between the portion where noise suppression processing is performed and the portion where noise suppression processing is not performed, and the image is unnatural. There is a risk of becoming.

  On the other hand, the technique disclosed in Patent Document 4 performs noise suppression processing on the image after shading correction with a noise reduction rate corresponding to the shading correction rate. According to this technique, by providing continuity in the noise reduction rate, unnaturalness due to the technique disclosed in Patent Document 3 can be avoided.

JP 2006-121612 A JP 2011-15277 A JP 2004-48562 A JP 2006-237686A

  However, there are various algorithms for noise suppression processing, and there are many that cannot control the noise reduction rate continuously according to only one parameter (for example, shading correction amount). For this reason, the technique disclosed in Patent Document 4 depends on the algorithm of the noise suppression process, and the case where it can be realized is limited.

  Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

  An image processing apparatus according to an embodiment performs a shading correction process and a noise suppression process on an image obtained by imaging. The shading correction process is a process of multiplying each pixel by a gain Gi (Gi ≧ 1) corresponding to the pixel position i corresponding to the image height of the lens.

  The image processing apparatus includes a first circuit that performs a first correction process, a second circuit that performs a second correction process and a second noise suppression process, and a synthesis circuit.

  The first correction process is a process of multiplying each pixel by a first gain GAi that is equal to or less than the gain Gi for each pixel position i in the central portion and smaller than the gain Gi for each pixel position i other than the central portion. .

  The second correction process is a process of multiplying each pixel by a second gain GBi that is a difference between the gain Gi and the first gain GAi.

  The synthesis circuit adds the image processed by the first circuit and the image processed by the second circuit for each pixel.

  Note that a representation of the image processing apparatus of the above embodiment replaced with a method or system, a program for causing a computer to execute the processing of the apparatus, an imaging apparatus including the apparatus, and the like are also effective as an aspect of the present invention. is there.

  According to the image processing apparatus of one embodiment, it is possible to improve image quality without limiting the algorithm of noise suppression processing.

1 is a diagram illustrating an image processing apparatus according to a first embodiment. The relationship between the gain of shading correction by the image processing apparatus according to the first embodiment shown in FIG. 1, the first gain used by the first correction circuit, and the second gain used by the second correction circuit is shown. FIG. It is a figure which shows the image processing apparatus concerning 2nd Embodiment. It is a figure which shows the image processing apparatus concerning 3rd Embodiment. It is a figure which shows the image processing apparatus concerning 4th Embodiment. It is a figure which shows the image processing apparatus concerning 5th Embodiment. It is a figure which shows the image processing apparatus concerning 6th Embodiment. The relationship between the gain of shading correction by the image processing apparatus according to the sixth embodiment shown in FIG. 7, the first gain used by the first correction circuit, and the second gain used by the second correction circuit is shown. FIG. It is a figure which shows the image processing apparatus concerning 7th Embodiment. It is a figure which shows the image processing apparatus concerning 8th Embodiment. The relationship between the gain of shading correction by the image processing apparatus according to the eighth embodiment shown in FIG. 10, the first gain used by the first correction circuit, and the second gain used by the second correction circuit is shown. FIG.

  For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Each element described in the drawings as a functional block for performing various processes can be configured by a CPU, a memory, and other circuits in terms of hardware, and a program loaded in the memory in terms of software. Etc. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof, and is not limited to any one. Note that, in each drawing, the same element is denoted by the same reference numeral, and redundant description is omitted as necessary.

  Further, the above-described program can be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROM (Read Only Memory) CD-R, CD -R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

<First Embodiment>
FIG. 1 shows an image processing apparatus 100 according to the first embodiment. The image processing apparatus 100 is provided, for example, in a digital camera, and obtains an image S1 by performing a shading correction process and a noise suppression process on an image S0 obtained by imaging with an imaging device. 101, a second circuit 102, and a synthesis circuit 130.

  The first circuit 101 includes a first correction circuit 110 that performs a first correction process. The first correction circuit 110 multiplies each pixel of the image S0 by a gain (first gain GAi) corresponding to the pixel position i to obtain a first corrected image SH1.

  The second circuit 102 includes a second correction circuit 120 that performs a second correction process, and a second noise suppression circuit 122 that performs a noise suppression process (second noise suppression process).

  The second correction circuit 120 multiplies each pixel of the image S0 by a gain corresponding to the pixel position i (second gain GBi) to obtain a second corrected image SH2.

  The second noise suppression circuit 122 performs a noise suppression process on the second corrected image SH2 obtained by the second correction circuit 120 to obtain a second noise suppression image SNR2.

  The synthesis circuit 130 adds the image obtained by the first circuit 101 (first corrected image SH1) and the image obtained by the second circuit 102 (second noise suppression image SNR2) for each pixel. An image S1 is obtained.

  With reference to FIG. 2, the gain (Gi) for each pixel of the image S0 corresponding to the target shading correction process (hereinafter referred to as “target shading correction process”) of the image processing apparatus 100, and the first correction A relationship between the first gain GAi used by the circuit 110 and the second gain GBi used by the second correction circuit 120 will be described.

  The gain Gi shown in FIG. 2 is a typical example of the gain of the normal shading correction process, and is “1” at the lens center (corresponding to the image center), and increases toward the outer periphery. The shape of the curve of the gain Gi varies depending on the design, but in general, the gain at the center is the smallest “1”.

  The first gain GAi is less than or equal to the gain Gi for each pixel position i in the center of the image, and is smaller than the gain Gi for each pixel position i other than the center. In the example shown in the drawing, the first gain GAi is “1” for the center pixel and increases as it goes to the outer periphery, similarly to the gain Gi, but at the same pixel position i, the first gain GAi is “1”. The gain GAi is equal to or less than the gain Gi.

  The second gain GBi is a difference between the gain Gi and the first gain GAi. That is, the sum of the first gain GAi and the second gain GBi becomes the gain Gi of the target shading correction process of the image processing apparatus 100.

  That is, the first correction circuit 110 and the second correction circuit 120 partially perform the target shading correction process of the image processing apparatus 100. Therefore, if the first correction image SH1 and the second correction image SH2 obtained by the first correction circuit 110 are added for each pixel, an image after the target shading correction processing of the image processing apparatus 100 is obtained.

  Conventionally, noise suppression processing is performed on an image after target shading correction processing, or shading correction processing is performed on an image after noise suppression processing. On the other hand, in the image processing apparatus 100 of the present embodiment, the second correction circuit 120 obtained by the second correction circuit 120 is not subjected to the noise suppression process on the first correction image SH1 obtained by the first correction circuit 110. Noise suppression processing is performed on the corrected image SH2. Then, the first correction image SH1 and the second noise suppression image SNR2 obtained by performing the noise suppression process on the second correction image SH2 are added for each pixel.

  Here, the second noise suppression circuit 122 is set so as to remove the average value or the maximum value of noise, which is normally performed on the image after the shading correction processing, with respect to the second corrected image SH2. Therefore, noise suppression processing that emphasizes noise removal is performed rather than detail storage. Therefore, a good noise suppression effect can be obtained.

  On the other hand, the first corrected image SH1 constituting a part of the image S1 is not subjected to noise suppression processing. Therefore, the details of the image S0 can be left in the image S1.

  Note that the ratio of the first gain GAi and the second gain GBi to the gain Gi may be adjusted according to the priority of noise suppression and detail storage. For example, when priority is given to noise suppression, the distance between the first gain GAi and the gain Gi is increased, and when priority is given to detail preservation, the distance between the first gain GAi and the gain Gi may be reduced. .

  In addition, the second noise suppression circuit 222 does not need to be limited to an algorithm that can continuously control the noise reduction rate according to only a single parameter (for example, shading correction amount). Can be applied.

  Also, in both methods of Patent Document 3 and Patent Document 4, whether to perform noise suppression processing or the noise reduction rate is determined according to the shading correction amount, so that noise suppression is performed from the functional block responsible for shading correction. It is necessary to transmit the shading correction amount to the functional block responsible for processing. Since the shading correction process and the noise suppression process are not necessarily performed continuously, the more processing between them, the larger the storage capacity for transmitting the shading correction amount.

  Instead of transmitting the shading correction amount, a method of holding the shading correction amount in advance by a functional block responsible for noise suppression processing is also conceivable. However, since the shading correction amount varies depending on the type of light at the time of imaging and the imaging mode, the functional block responsible for noise suppression processing holds the shading correction amount in all cases in order to handle all cases. The storage capacity for that would be enormous. The same applies to the case where the shading correction is performed after the noise suppression processing.

  On the other hand, the second correction circuit 120 in the image processing apparatus 100 performs noise suppression processing based on the first corrected image SH1 itself, and does not refer to the shading correction amount, so that the shading correction amount is transmitted or retained. Does not require storage capacity. Therefore, image quality can be improved with a small circuit scale.

<Second Embodiment>
FIG. 3 shows an image processing apparatus 200 according to the second embodiment. Similarly to the image processing apparatus 100, the image processing apparatus 200 is provided in, for example, a digital camera, and obtains an image S1 by performing a shading correction process and a noise suppression process on the image S0 obtained by imaging with the imaging device. It is. Assume that the gain of the target shading correction process of the image processing apparatus 200 is the same as the gain Gi of the target shading correction process of the image processing apparatus 100.

  The image processing apparatus 200 has the same configuration as that of the image processing apparatus 100 except that the second circuit 202 is different from the second circuit 102 in the image processing apparatus 100. The relationship between the first gain GAi used for the first correction process performed by the first circuit 101 and the second gain GBi used for the second correction process performed by the second circuit 202 is also an image. This is the same as in the case of the processing apparatus 100.

  Similarly to the second circuit 102, the second circuit 202 performs a second noise suppression process and a second correction process, and includes a second noise suppression circuit 122 and a second correction circuit included therein. 120 is the same as the functional block corresponding to the phase included in the second circuit 102.

  In the second circuit 202, the order of the second noise suppression process and the second correction process is opposite to that in the second circuit 102. As shown in the figure, the second circuit 202 first performs noise suppression processing (second noise suppression processing) on the image S0 by the second noise suppression circuit 122 to generate the second noise suppression image SNR2. Get. This second noise suppression process is also a noise suppression process in which noise removal is more important than detail storage.

  Then, the second correction circuit 120 applies a second gain GBi (gain Gi) corresponding to the pixel position i to each pixel of the second noise suppression image SNR2 obtained by the second noise suppression circuit 122. And the difference between the first gain GAi) to obtain a second corrected image SH2.

  The synthesis circuit 130 adds the image output from the first circuit 101 (first corrected image SH1) and the image output from the second circuit 202 (here, the second noise suppression image SNR2) for each pixel. Thus, an image S1 is obtained.

  In the image processing device 200, the second noise suppression processing performed by the second circuit 202 and the second correction processing are performed in the same order as the second noise suppression processing performed by the second circuit 102 in the image processing device 100. The image processing apparatus 100 is the same as the image processing apparatus 100 except that the order of the second correction processing is reversed, and the same effect as the image processing apparatus 100 can be obtained.

<Third Embodiment>
FIG. 4 shows an image processing apparatus 300 according to the third embodiment. Similarly to the image processing apparatus 100, the image processing apparatus 300 is also provided in, for example, a digital camera, and obtains an image S1 by performing shading correction processing and noise suppression processing on the image S0 obtained by imaging with the imaging device. It is. Assume that the gain of the target shading correction process of the image processing apparatus 300 is the same as the gain Gi of the target shading correction process of the image processing apparatus 100.

  The image processing apparatus 300 is the same as the image processing apparatus 100 except that the image processing apparatus 300 further includes a first noise suppression circuit 310.

  In the image processing apparatus 100, the first circuit 101 and the second circuit 102 perform a first correction process and a second correction process on the image S0, respectively.

  On the other hand, in the image processing apparatus 300, before the first circuit 101 and the second circuit 102, the first noise suppression circuit 310 first performs noise suppression processing (first noise suppression processing) on the image S0. )I do.

  The first noise suppression process performed by the first noise suppression circuit 310 is a noise suppression process that places importance on saving suppression details rather than noise removal, such as removing the minimum noise value. Therefore, the noise suppression process by the first noise suppression circuit 310 is weaker than the noise suppression process performed by the second noise suppression circuit 122 included in the second circuit 102.

  The image (first noise suppression image SNR1) obtained by the first noise suppression circuit 310 is input to the first circuit 101 and the second circuit 102.

  The first circuit 101 and the second circuit 102 perform processing on the first noise-suppressed image SNR1 instead of the image S0. The contents of these processes are the same as the processes of the first circuit 101 and the second circuit 102 in the image processing apparatus 100.

  The image processing apparatus 300 can obtain all the effects obtained by the image processing apparatus 100. In addition, the first correction image SH1 output from the first correction circuit 110 is also noise because the image S0 is subjected to the noise suppression process of the minimum source and then used for the first circuit 101 and the second circuit 102. Is suppressed, and noise in the image S1 can be reduced as compared with the case of the image processing apparatus 100.

  The image processing apparatus 300 is obtained by adding a first noise suppression circuit 310 to the image processing apparatus 100 shown in FIG. The first noise suppression circuit 310 may be added before the first circuit 101 and the second circuit 202 in the image processing apparatus 200 shown in FIG. Further, by adding the first noise suppression circuit 310 to the image processing apparatus 200, the same effect as that of the image processing apparatus 300 can be obtained.

<Fourth embodiment>
FIG. 5 shows an image processing apparatus 400 according to the fourth embodiment.
In the image processing apparatus 300 according to the third embodiment illustrated in FIG. 4, a first noise suppression circuit 310 that performs a first noise suppression process is provided before the first correction circuit 110 and the second circuit 102. It has been.

  On the other hand, in the image processing apparatus 400, the first noise suppression circuit 310 is provided after the synthesis circuit 130. Except for this point, the image processing apparatus 400 is the same as the image processing apparatus 300.

  In other words, the image processing apparatus 400 uses the first circuit 101 for the first correction process (first correction image SH1), the second circuit 102 performs the second correction process and the second noise suppression. The image S1 obtained by adding the processed image (second noise suppression image SNR2) for each pixel is subjected to a first noise suppression process that emphasizes preservation of detail rather than noise removal. Then output.

  Therefore, the image (first noise suppression image SNR1) output by the first noise suppression circuit 310 is the same as the image (image S1) output by the synthesis circuit 130 in the image processing device 300. Therefore, the image processing apparatus 400 can obtain the same effects as the image processing apparatus 300.

<Fifth embodiment>
FIG. 6 shows an image processing apparatus 500 according to the fifth embodiment. The image processing apparatus 500 is the same as the image processing apparatus 100 except that the first circuit 501 is different from the first circuit 101 in the image processing apparatus 100.

  In the image processing apparatus 300 illustrated in FIG. 4, the first noise suppression circuit 310 is provided in front of the first circuit 101 and the second circuit 102. In the image processing apparatus 400 shown in FIG. 5, the first noise suppression circuit 310 is provided after the synthesis circuit 130. An image processing apparatus 500 illustrated in FIG. 6 is an example in which the first noise suppression circuit 310 is provided in the first circuit 501.

  As shown in FIG. 6, the first circuit 501 of the image processing apparatus 500 includes a first correction circuit 110 and a first noise suppression circuit 310.

  The first correction circuit 110 multiplies each pixel by a first gain GAi corresponding to the pixel position i, similarly to the first correction circuit 110 in the image processing apparatus of each embodiment described above. Thus, a first corrected image SH1 is obtained.

  The first noise suppression circuit 310 performs a first noise suppression process on the first corrected image SH1 obtained by the first correction circuit 110, which emphasizes preservation of detail rather than noise removal. 1 noise suppression image SNR 1 is obtained and output to the synthesis circuit 130.

  The synthesis circuit 130 outputs, for each pixel, the image output from the first circuit 501 (here, the first noise suppression image SNR1) and the image output from the second circuit 102 (second noise suppression image SNR2). The image S1 is obtained by addition.

  The image processing apparatus 500 can also obtain the same effects as the image processing apparatus 100. Before outputting the image (first corrected image SH1) subjected to the first correction processing by the first correction circuit 110 to the synthesis circuit 130, the first noise suppression processing is performed on the first correction image SH1. Therefore, noise in the image S1 can be reduced as compared with the case of the image processing apparatus 100.

  Of course, with respect to the image processing apparatus 500 shown in FIG. 6, the front and rear order of the second correction circuit 120 and the second noise suppression circuit 122, or the front and rear of the first correction circuit 110 and the first noise suppression circuit 310. The order may be reversed.

<Sixth Embodiment>
FIG. 7 shows an image processing apparatus 600 according to the sixth embodiment. The image processing apparatus 600 includes a first circuit 601, a second circuit 102, and a synthesis circuit 130, except that the first circuit 601 is provided instead of the first circuit 101. It is the same. In the image processing apparatus 600, the first circuit 601 includes a first correction circuit 610.

  In the image processing apparatus 100, the first gain GAi used by the first correction circuit 110 included in the first circuit 101 differs depending on the pixel position i.

  On the other hand, in the image processing apparatus 600, the first gain GAi used by the first correction circuit 610 has the same value regardless of the pixel position i. The same value can be any value greater than 0 and less than or equal to 1.

  FIG. 8 shows the gain Gi of the target shading correction process, the first gain GAi used by the first correction circuit 610, and the second gain GBi used by the second correction circuit 120 in the image processing apparatus 600.

  In the illustrated example, the first gain GAi is “0.8” regardless of the pixel position i. The second gain GBi is a difference between the gain Gi and the first gain GAi.

  Since the image processing apparatus 600 can obtain all the effects of the image processing apparatus 100 and the first correction circuit 610 multiplies the first gain GAi having the same value for all pixels, The first correction circuit can be easily configured from the image processing apparatus 100.

<Seventh embodiment>
The first correction circuit 610 in the image processing apparatus 600 may be applied to the image processing apparatuses of all the embodiments other than the image processing apparatus 600. An image processing apparatus 700 according to the seventh embodiment illustrated in FIG. 9 is an example in which the first correction circuit 610 is applied to the image processing apparatus 300 according to the third embodiment illustrated in FIG. 4.

  As shown in FIG. 9, the image processing apparatus 700 is different from the first circuit 101 including the first correction circuit 110 in that a first circuit 601 including the first correction circuit 610 is provided. This is the same as the image processing apparatus 300.

<Eighth Embodiment>
FIG. 10 shows an image processing apparatus 800 according to the eighth embodiment. In the image processing apparatus 800, the first correction circuit that performs the first correction process is different from the first correction circuit in the image processing apparatuses of the other embodiments. The first correction circuit in this image processing apparatus 800 can be applied to the image processing apparatus of any of the above-described embodiments. As an example, the image processing apparatus of the fifth embodiment shown in FIG. The case where it is applied to 500 will be described.

  The image processing apparatus 800 is the same as the image processing apparatus 500 except that a first circuit 801 is provided instead of the first circuit 501. The first circuit 801 is the same as the first circuit 501 except that the first correction circuit 810 is provided instead of the first correction circuit 110.

  In the image processing apparatus 500, the first correction circuit 110 multiplies each pixel by a first gain GAi corresponding to the pixel position i as shown in FIG. On the other hand, in the image processing apparatus 800, the first correction circuit 810 multiplies all the pixels by the first gain GAi that is “1”.

  That is, in the image processing apparatus 800, the first correction circuit 810 is a delay circuit and does not adjust the gain for the image S0.

  FIG. 11 shows the gain Gi of the target shading correction process, the first gain GAi used by the first correction circuit 810, and the second gain GBi used by the second correction circuit 120 in the image processing apparatus 800.

  As shown in the figure, the first gain GAi is “1” regardless of the pixel position i. The second gain GBi is a difference between the gain Gi and the first gain GAi.

  The image processing apparatus 800 can obtain all the effects of the image processing apparatus 500. Further, since the first correction circuit 810 is a delay circuit, the first correction circuit can be configured with a simpler and smaller circuit scale than the image processing apparatus 500. This also applies to the case where the first correction circuit 810 is applied to the other embodiments.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the embodiments already described, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

  For example, in the image processing apparatus 500 and the image processing apparatus 800, the first noise suppression circuit and the second noise suppression circuit are provided as different blocks. These two noise suppression circuits are provided as one block, respectively. The noise suppression process may be switched.

  In addition, for example, black level correction processing or scratch correction processing may be performed on the image S0 and then input to the first correction circuit and the second correction circuit.

  Further, a block for performing other processing may be provided between the first correction circuit and the synthesis circuit and between the second correction circuit and the synthesis circuit.

DESCRIPTION OF SYMBOLS 100 Image processing apparatus 101 1st circuit 102 2nd circuit 110 1st correction circuit 120 2nd correction circuit 122 2nd noise suppression circuit 130 Composition circuit 200 Image processing apparatus 202 2nd circuit 300 Image processing apparatus 310 First noise suppression circuit 400 Image processing device 500 Image processing device 501 First circuit 600 Image processing device 601 First circuit 610 First correction circuit 700 Image processing device 800 Image processing device 801 First circuit 810 First Correction circuit Gi gain of target shading correction processing GAi first gain GBi second gain S0, S1 image SH1 first correction image SH2 second correction image SNR1 first noise suppression image SNR2 second noise suppression image

Claims (3)

A shading correction process and a noise suppression process are performed on an image obtained by imaging, and the shading correction process is performed for each pixel with a gain Gi (in accordance with a pixel position i corresponding to the image height of the lens. In the image processing apparatus that is a process of multiplying Gi ≧ 1),
A first circuit, a second circuit, a synthesis circuit, and a first noise suppression circuit ;
The first circuit includes:
For each pixel position i in the central part, a first correction process is performed to multiply each pixel by the gain Gi or less, and for each pixel position i other than the central part, a first gain GAi that is smaller than the gain Gi. ,
The second circuit includes:
Performing a second noise suppression process and a second correction process for multiplying each pixel by a second gain GBi that is the difference between the gain Gi and the first gain GAi;
The synthesis circuit is:
And image processed by the first circuit, and image processed by the second circuit is added for each pixel,
The first noise suppression circuit includes:
Performing a first noise suppression process on the image and providing the first circuit and the second circuit;
Or
Applying the first noise suppression process to the image obtained by the synthesis circuit,
The first noise suppression process is a noise suppression process that emphasizes the preservation of detail rather than noise removal,
The second noise suppression process is an image processing apparatus that is a noise suppression process that emphasizes noise removal rather than detail storage . A shading correction process and a noise suppression process are performed on an image obtained by imaging, and the shading correction process is performed for each pixel with a gain Gi (in accordance with a pixel position i corresponding to the image height of the lens. In the image processing apparatus that is a process of multiplying Gi ≧ 1),
A first circuit, a second circuit, and a synthesis circuit;
The first circuit includes:
A first correction process for multiplying each pixel by a first gain GAi that is equal to or less than the gain Gi for each pixel position i in the central portion and is smaller than the gain Gi for each pixel position i other than the central portion ; Performing the first noise suppression process ,
The second circuit includes:
Performing a second noise suppression process and a second correction process for multiplying each pixel by a second gain GBi that is the difference between the gain Gi and the first gain GAi;
The synthesis circuit is:
And image processed by the first circuit, and image processed by the second circuit is added for each pixel,
The first noise suppression process is a noise suppression process that emphasizes the preservation of detail rather than noise removal,
The second noise suppression process is an image processing apparatus that is a noise suppression process that emphasizes noise removal rather than detail storage . The first correction processing multiplies all the pixels by the first gain GAi having the same value of 1 or less.
The image processing apparatus according to claim 1 .

Images